Conventionally, paper such as a corrugated board has been used as a cushioning material or a packaging material for transport. In recent years, a material generating neither paper dust nor volatile organic compounds has been required for the cushioning material or the packaging material for transporting glass plates used for flat panel displays for liquid crystal televisions or plasma televisions, precision electronic components or the like. Thus, a sheet formed of a polyolefin-based resin (Patent literature No. 1 as described below) and a foamed sheet formed of a polyolefin-based resin (Patent literatures No. 2, 3 and 4 as described below) have been proposed.
Moreover, considering a demand for preventing deposition of dirt and dust due to static electricity during packaging and transport, a cushioning material where an antistatic agent is kneaded into a polyolefin-based resin foamed sheet itself (Patent literatures No. 5 and 6 as described below), and a packaging material on which a polyolefin-based resin film containing a high molecular antistatic agent is laminated (Patent literature No. 7 as described below) have been proposed.
However, a problem exists in that low-molecular-weight volatile components contained in the polyolefin-based resin are transferred onto an article to be packed to cause contamination and affect the glass plates or the precision electronic components. The antistatic agent is unable to address this because the antistatic agent is trapped in a foamed air layer. Moreover, the foamed sheet takes up much space during transportation because the sheet is thick.
As a thinned product, use of a thin nonwoven fabric sheet formed of a polyester continuous fiber has been proposed in which heat embossing is applied and a contact area ratio is decreased (Patent literature No. 9). However, when a polyester is used for a fiber, a sufficient antistatic effect is not obtained because melting at a high temperature is necessary, and consequently decomposition of the antistatic agent easily occurs.
Moreover, an antistatic sheet limited to a specific polypropylene resin from a stand point of compatibility of a polymer antistatic agent has been proposed for transporting electronic components (Patent literature No. 8).
However, the resin as proposed in Patent literature No. 8 is a high viscosity resin intended for a sheet or a film, and hence cannot be used for a fiber. If the resin is used for the fiber, a sufficient antistatic effect is not obtained because melting at a high temperature is necessary, and consequently decomposition of the antistatic agent occurs.
In a high molecular resin such as the polyolefin-based resin, generally (refer to Non-patent literature No. 1), an antistatic effect tends to become harder to obtain as density increases in order of low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE). Therefore, only a small number of products are constituted of a high density polyethylene resin, particularly, among formed products obtained from the polyolefin-based resin.